A mass blackout across Spain, Portugal and south-western France in April 2025 pushed grid-failure concerns up the agenda. In Lancaster, the 2015 floods cut power to 61,500 people in the city. Professor Roger Kemp gathered people to examine what had gone wrong; he described the aftermath as “almost like a zombie movie”. Streetlights were off, most cash machines did not work, and there was a huge queue at the one working telephone box.
A phrase often heard in contingency circles sums up the thinking: “We are nine meals from anarchy”, a reminder of fears that three days without food would be enough to turn a crisis into chaos. The government’s “Be Ready” campaign is designed to help households prepare for possible crises, though the government says there is no specific threat to the grid.
The BBC has detailed its own Black Sky plan. About 100 people in the BBC would run a special emergency radio studio with secure lines of communication that do not depend on the internet. Broadcasts would be sent via radio transmission towers isolated from the internet. The towers have tanks of between five and 40,000 litres (8,800 gallons) of diesel to keep their generators going for three days. “It was originally thought we should plan for five to seven days,” a BBC insider said. “The latest advice from Neso (National Energy System Operator) is that they will probably be able to get the power back on in two to three days.”
Lord Harris, chair of the National Preparedness Commission, said a blackout would do more than turn off the lights: it would likely stop water supplies. He said sewage tends to solidify unless water can move through it, causing blockages and sewage to flow out and back up the system. He also warned that the emergency services’ move to mobile-network-based radio communications means “if the mobile phone goes down it will also impact on emergency services communications”. The government says moving emergency services onto modern 4G and 5G technologies is “resilient and reliable”.
The UK's copper wire landline network is due to be switched off on 31 January 2027. In Lancaster, copper landlines and FM radio were the two communication systems that survived. “If anything, we've gone backwards,” Professor Kemp said. “Switching off the public switch telephone network, I think shows that there has been really no thought at all about how you communicate when you've no longer got power.”
Separately, the government is investing £70m in High Altitude Pseudo-Satellites (HAPS), aircraft designed to circle the UK and provide emergency mobile and internet connectivity for at least a week at times of crisis.